Printing telegraph apparatus



Feb. 16, 1943- c L N 2,310,967

PRINTING TELEGRAPH APPARATUS Original Filed April 25, 1938 24 FIG.2 F|G.1

INVENTOR. C ARL A. LEVIN Patented Feb. 16, 1943 2,310,967 PRINTING TELEGRAPH APPARATUS Carl A. Levin, Chicago, 111., assignor to Teletype Corporation, Chicago, 111., a corporation of Delaware Application December 30, 1939, 'Serial No. 311,767, which is a division of application Serial No. 204,038, April 25, 1938. Divided and this application February 27, 1941, Serial No. 380,911

Claims.

This invention relates to printing telegraph apparatus and more particular to printing telegraph apparatus in which the characters are printed from type elements carried upon the periphery of a rotatable and selectively arrestable type wheel.

This application is a division of application Serial No. 311,767, filed December 30, 1939, by C. A. Levin which is a division of C. A. Levin application Serial No. 204,038, filed April 25, 1938, and now Patent No. 2,230,463, issued February 4, 1941.

An object of the invention resides in the provision, in a printing telegraph receiving unit embodying a type wheel having displaceable type elements, of instrumentalities for actuating said elements, capable of extremely rapid positive operation.

The invention features apparatus for actuating the individual type elements of a type wheel including a print hammer which is actuated by a cam follower and having a yieldable element included in the linkage interposed between the print cam and the print hammer whereby the actual printing operation is performed by the expenditure of kinetic energy of the print hammer and possibly an additional element or elements, such kinetic energy resulting in overtravel of the print hammer permitted by the yieldable element.

According to the present invention, a reciprocatable printing member is provided for actuating the type elements individually. A bail carries the follower roller which engages the periphery of a printing cam, the bail being biased into engagement with the cam by a tension spring. Operation of the printing member is effected when the printing bail cam follower roller rides down an abrupt drop in the printing cam. The distance through which the printing bail is operated by its spring is insufficient to bring the printing member into engagement with a type element. A spring is interposed between the printing bail and the printing member, and the inertia of the element to which motion is imparted by the printing bail causes that element to overtravel, the interposed spring yielding and permitting the overtravel, and the amount of overtravel being sumcient to cause a selected type element to effect printing. The spring which yields and permits the overtravel immediately retracts the printing element to unoperated position, thereby clearing the path of unoperated type elements so that the type wheel may be rotated to a new position.

The type wheel used with this improved type actuating mechanism may be of any suitable construction but preferably is the type wheel shown in detail and claimed in the copending application of C. A. Levin, Serial No. 311,767, filed December 30, 1939, of which this application is a division. In this preferred form of type wheel, the drum portion which joins the upper and lower flanges has a peripheral rib intermediate the upper and lower flanges. The rib thus divides the surface of the drum into two peripheral grooves which serve as seats for the garter springs and confine the springs in the desired position. The type wheel is otherwise substantially the same as that shown in Patent No. 2,180,360 of November 21, 1939 to H. L. Krum et a1.

For a complete understanding of the invention reference may be had to the following detailed description to be interpreted in the light of the accompanying drawing wherein Fig. 1 is a plan view of a portion of a printing telegraph apparatus with parts broken away to show more clearly the features of the printing mechanism according to the present invention;

Fig. 2 is a fragmentary detail perspective view of the type actuating mechanism; and

Fig. 3 is a view partly in elevation and partly in section showing details of the type pallet operating mechanism or printing mechanism and of the type wheel, the type pallet operating" they are shown and described in great detail in the patent to Albert H. Reiber, No. 2,247,408, July 1, 1941, and are not essential to an understanding of the present invention.

Referring to the drawing, wherein like reference characters designate the same parts throughout the several views, the reference numeral 26 designates a print hammer operating lever which is in the form of a bell crank lever and comprises arms 21 and 28. The free end of the arm 2'! supports a cam follower roller 28 which engages the periphery of a print controlling cam 3| which may be identical with the print controlling cam of the Reiber patent, above identified, and may operate in exactly the same manner and according to. the same timing as the controlling cam of said Reiber patent. The lever 26 is pivoted on a pivot rod 25, provided at its upper end with a retaining screw 32 which serves to retain a bell crank 31 in place. Ann 28 of lever 26 is provided with an arc slot 33, the center of the arc of which cides with the pivotal axis of lever 26 which is the axis of pivot rod 26. A clamping screw 34 extends through slot 33 and is threaded in one arm 36 of the bell crank lever 31. Bell crank 31 is pivoted on the pivot rod 25 coaxially with lever 26, the screw 32 serving as the upper pivot for the bell crank 31 on pivot rod 26. Ann,

36 of hell crank 31 rests upon arm 28 of bell crank 26 and screw 34 clamps the two arms rigidly together, the slot 33 affording provision for angular adjustment of bell crank lever 31 relative to bell crank lever 26. Bell crank 31 has an arm 38 disposed in a horizontal plane considerably above that in which arm 36 is located and approximately in the plane of the type wheel with which the present type actuating mechanism is to co-operate. A vertical bar 39 integral with arms 36 and 38 interconnects the two arms and completes the bell crank 31. Upper arm 38 of bell crank 31 is provided with a plurality of apertures 4| any one of which may receive one end of a tension spring 42, the other end of which is connected to a stationary bracket 43. Spring 42 biases bell crank 31 in a counterclockwise direction' and thus urges the cam follower roller 23 into engagement with the periphery of cam 3|. Spring 42 furnishes the power for actuating the type pallet of the type wheel and by shifting the foremost end of spring 42 from one to another of the holes 4|, the tension of spring 42 may be increased or decreased as desired and, correspondingly, its effect upon the type hammer to be described will be varied. It should be noted that roller 23 is shown in Fig. l at the high point of cam 3| just before the roller passes oil the high spot, whereas in Fig. 2 the roller is engaging the low point of the cam.

At its free end, arm 36 of bell crank 31 carries a screw 44 (Fig. 3) which supports a spring post 46. A print hammer or type pallet operating member 41 is provided in its foremost end with an open ended slot 48 which fits over the screw 44, the forward end of print hammer 41 resting upon arm 38 of bell crank 31. Print hammer 41 is guided and further supported for reciprocation by a bracket 43 which may be similar to the bracket provided for guiding the print hammer in the Reiber patent above identified. A tension spring which has one end engaging the print hammer 41 and the other end engaging the spring post 46, urges print hammer 41 to its extreme position of retraction which may be determined by the engagement of the closed end of the slot 48 with the screw 44 or by the engagement of a laterally extending projection 52 of the print hammer 41 with an adjustable eccentric 53 secured to a plate H which supports ribbon spools I6. Print-hammer 41 is provided with a shoulder 54 which comes into engagement with the adjustable eccentric 53 when the print hammer is reciprocated rearwardly of the printing telegraph receiving unit to limit the operating strokes of the print hammer and prevent excessive reciprocation of the type pallet.

In Fig. 1, the printing mechanism is shown in the condition which exists just before a printing operation, bail 26 and bell crank 31 being in their extreme clockwise position and the free end of the print hammer 41 being retracted well back from the type pallet. As cam follower roller 28 traverses the drop-oi! in cam 3|, lever 26 and bell crank 31 are rocked by spring 42 to their extreme counterclockwise position, the movement to this position being relatively sharp. Screw 44 engages the inner or closed end of the slot 48 in the print hammer 41'and positively moves the print hammer toward the inner end of the type pallet which is aligned with the hammer at that time. The positive movement of the print hammer 41 by bell crank 31 ceases when the cam follower roller 23 engages the innermost portion of the periphery of cam 3|,

and the termination of the positive movement occurs just before the free end of the print hammer 41 engages the type pallet aligned with it. The inertia of the print hammer 41 causes the hammer to continue to move rearwardly or toward the back of the printing unit after the bell crank 31 has been arrested, the inner end of slot 48 moving away from screw 44 and spring 5| yielding to permit the additional or overtravel movement of the print hammer.

The overtravel of the print hammer 41 is sumcient to drive the type pallet in front of it radially of the type wheel to effect printing, the free end of the print hammer 41 moving into the space between the type pallets on either side of the one actuated. As soon as the kinetic energy of print hammer 41 has been dissipated, spring 5| retracts the print hammer until the inner end of the slot 48 engages screw 44 or until projection 52 engages eccentric 63, and such retmction is sufllcient to withdraw the free end of the print hammer from between the type pallets even though the rotation of the cam 3| may not have been sufllcient to begin the movement of the ball 26 and bell crank 31 in a clockwise direction. From the foregoing it will be apparent that printing is accomplished by overtravel of the print hammer in a manner decidedly different from that shown in the aforementioned patent to Albert H. Reiber and that only the print hammer 41 overtravels whereas in the embodiment shown and defined in the Reiber patent the bell crank to which the print hammer is attached also overtravels.

Although as pointed out hereinbefore any suit able type wheel may be utilized with the type actuating mechanism described herein, the type wheel which is preferably used is the one covered in the copending application of C. A. Levin, Serial No. 311,767, filed December 30, 1939. As clearly shown in Fig. 3 the type wheel is designated generally by the reference numeral 86 and comprises a foundation in the form of a cast or turned wheel which may comprise upper and lower flanges 6| and 62 respectively joined by an integral drum portion '63. The inner surface of the drum portion 63 is cylindrical and the external drum surface includes a ridge 64' integral with the drum portion 63 and located midway between the flanges 6| and 62. The face of ridge 64 may be fiat and the sides thereof are curved toward the flanges 6| and 62, the inner faces of which also curve to meet the curving sides of ridge 64 and form therewith spaced annular grooves of semi-circular cross section. A plurality of radially directed type pallet slots is provided in the type wheel 86, the slots being cut entirely through the drum portion 63 but only partially through the thickness of flange 6|.

Each of the slots in the type wheel receives and slidably supports the shanks it of two type pallets 81. The type pallet shanks i8 extend into the interior of type wheel ll sui'iiciently iar that they may be engaged and actuated by the print hammer 41 to eflect printing. The type pallets 81 in the upper row have their shanks 66 notched as shown at 68, the notches opening downwardly, and those in the lower row have similar notches 68 which open upwardly. A garter spring 69 extends through all of the notches 68 of the type pallets 81 in a row and biases them to their innermost position radially oi the type wheel. The annular ridge 64, which in cooperation with the inner faces of the flanges 8i and 62 defines the peripheral groove mentioned hereinbefore, separates the garter springs I9 and maintains them in the desired position. When any type pallet 81 is driven outwardly radially of the type wheel II by the print hammer 41 the garter spring 6! which engages the shank of the typ pallet distends slightly, thus permitting movement of the type pallet, and thereafter restores the pallet to the innermost position.

In this manner, any time that a print hammer 41 is driven forward by its cam and then snapped rearwardly by the spring 42 when the roller 2! moves of! the high portion of the cam II, the type printing hammer will cause a type pallet in alignment with it to be snapped outwardly against a page of paper on a platen 24. The type wheel '8 is suitably positioned on a type wheel support It and may be moved to position where the print hammer 41 will be in alignment with either the upper or lower row of type pallets in the type wheel so that either the upper or lower case characters may be printed, all in the manner more fully described in the patent to Reiber mentioned herelnbefore.

Although a specific embodiment of the invention has been described herein, it will be understood that the invention is not limited to such a speciiic form but is capable of adaptation, modification and rearrangement and is therefore tobelimitedonlybythescopeoftheappended claims.

What is claimed is:

1. In a printing telegraph apparatus, a type wheel having radially reciprocatable type elements, an operating cam, a cam follower lever, a bell crank pivoted coaxially with said cam follower lever, means for adiustably clamping said bell crank lever to said cam follower lever, spring means associated with said bell crank lever for urging said cam follower lever into engagement with its operating cam, a reciprocatable print hammer member having one end engaging said bell crank lever and the other end disposed inside said type wheel adjacent to the type elements, and a yield spring interconnecting said print hammer and said bell crank.

2. In a printing telegraph apparatus, a type,

wheel having radially reciprocatabie type elements, a cyclically operable cam, a cam iollower lever movable between extreme. clockwise and counterclockwise positions under the control of said cam, a bell crank lever having its axis c0- axial with that of said follower lever, means for adjustably clamping said bell crank lever to said cam follower lever, means associated with said bell crank lever for urging said cam follower lever into engagement with said cam, a reciprocatable print hammer for reciprocating said type elements individually, said print hammer having pin and slot connection with said bell crank lever, and yieldable means interconnecting said print hammer and said bell crank lever and normally tending to keep said print hammer in a position of extreme retraction with respect to said bell crank lever, said yieldable means enabling said print hammer to overtravel by the expenditure of kinetic energy after having been moved positively a predetermined distance by said bell crank lever.

3. In a printing telegraph apparatus, a plurality of type elements, a print hammer for operating said elements, an actuating lever for said print hammer, resilient means for urging said print hammer into abutting relationship with said actuating lever, and means to operate said actuating lever to positively drive said print hammer through a predetermined portion of its stroke, said resilient means enabling said print hammer to move away from said actuating lever to travel the last portion of its stroke by momentum against the influence of said resilient means.

4. In a printing telegraph apparatus, a plurality of type elements, a type operating member for operating said elements, said member having a slot, actuating means for said member having a pin engageable in said slot, resilient means for urging the slotted portion of said operating member into engagement with the pin of said actuating means, and means to operate said actuating means to positively drive said type operating member through a portion of its stroke, said resilient means enabling the slotted portion of said type operating element to move away from the pin of said actuating means to thereby enable said type operating member to travel the last portion of its stroke under momentum against the influence of said resilient means.

5. In a printing telegraph apparatus, a plurality of type elements, a type operating member for operating said elements, said member having a slot, actuating means for said member having a stud engageable in said slot, spring means for urging the slotted portion of said operating member into engagement with the stud of said actuatingmeans,andcamcontrolledmeanstooperate said actuating means to positively drive said type operating member through a portion of its stroke, said spring means enabling the slotted portion of said type operating element to move away from the stud of said actuating means to thereby enable said type operating member to travel the last portion of its stroke under momentum against the influence of said spring means.

CARL A. LIVIN. 

